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Questions tagged [propeller]

Aircraft propellers are airfoils which convert rotary motion from a piston or turbine engine into thrust suitable for propelling an aircraft.

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What are these aircraft? Seen in silhouette over Palm Springs

Screen capture on iMac, of photo posted and claimed taken 11/21/15. Palm Springs, CA
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What are the advantages of more than 4 propeller blades?

I have heard that propellers with more than four blades are not as efficient as 4 or less blades because of lower thrust which may result from interfering prop-streams. But I see the ATR-42/72 and ...
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Why should a test flight should be performed when the propellers are changed?

From this question I've learned that after a propeller change the plane should go through a test flight. Why is this?
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Are propellers obsolete? [duplicate]

Now that we have jet engines and all, is there still a use for propeller based flight (besides helicopters)? Most airlines nowadays don't use propellers, right?
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Why does this calculation show Gustave Whitehead's propellers were more than 100% efficient?

I have tried to calculate the efficiency of Gustave Whitehead's propellers using the information he provided to the American Inventor Magazine in 1902 (see the citation below). Number of propellers = ...
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Is this a good or a bad propeller?

I want to see if a propeller is bad or good for generating static thrust. This is what I know about the propeller and the engine used to turn it during a test: Engine shaft power, $P$ = 0.58 hp ...
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Why do turbofan blade tips exceed the speed of sound while prop tips should not?

It seems that the tips of the fan of a turbofan engine can and do break the sound barrier: The GE-90 has a fan diameter of 3124 mm and a rotational speed of 3475 RPM. Their circumferential velocity ...
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How much distance do I need between quadcopter propellers to avoid issues?

For a given propeller size (say 5"), what is the minimum clearance needed between propellers to ensure that not only do they not hit each other (easy to calculate), they also don't interfere too much ...
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Do quadcopter propellers break the sound barrier?

I recently bought a quadcopter and noticed every time I fly it there is this weird buzzing noise. I have heard this noise on other quadcopters around the same size as mine(4in by 4in). On an airliner ...
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What is the incidence angle of a propeller in the terminology of the Wright Brothers and how did they obtain it?

What is the angle of incidence of a propeller in the terminology of the Wright Brothers and how did they obtain it? In Feb. 1903 (see Screw Test 1903, page 8), using a 0.58 hp engine, the Wright ...
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How did Wilbur Wright create and use the formulas he mentions in his letter to Octave Chanute?

In a letter written by Wilbur Wright and addressed to Octave Chanute, dated 1903/06/18, I have found two things that I do not quite understand. Our engine develops at the brake 15.6 horse power and ...
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How is mass flow rate computed?

I have been wondering how the mass flow rate is determined by the area of the engine air intake surface and the incoming speed of the air. In still air, it is understandable that a stationary engine ...
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What are these circles around the propeller?

(Source: www.airliners.net) These circles I believe are the wing tip vortex formed by the propeller tips or is it just due to the rotation of the propeller. How does this occur?
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What happened to the blades in this picture?

Here is the picture Source:(brians-travels.com) This looks like a photoshopped picture, but I believe it isn't. Is this some kind of strange occurrence that occurs only with the human eye? The ...
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Would a headwind result in a faster propeller rpm?

A few weeks ago I did an experiment with a model aircraft that has a motorized propeller. I turned on the propeller and it turned at a constant speed. Then I turned on a desk fan and put it in front ...
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What is downwash on a wing and how does it form? [duplicate]

This is a subject I have been very confused with lately about thrust coming from downwash on a propeller and helicopter, but to understand how the downwash increases thrust is to know how it forms and ...
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How do the propeller blades accelerate air resulting in thrust to push an aircraft forward? [duplicate]

I do know that the blades on a propeller generate lift to provide a force pushing back on the air based on newton's law the 2nd. What I am having trouble understanding is how the blades generate ...
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Would an aircraft with contra-rotating propellers longer than the plane's wingspan be able to fly?

I enjoy taking the time to try and visualize how fictional aircraft might actually work in reality. Unfortunately there are some that seem highly impractical from an engineering student's point of ...
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Why does the Pilatus PC-12 go faster than the King Air C90?

Pilatus PC-12 (source: www.what2fly.com) King Air C90 (source: www.ok-aircraft.cz) I am wondering this because of the blades on the propellers on both of the planes. The Pilatus PC-12 can travel up ...
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How is thrust generated by a propeller? [duplicate]

I get confused sometimes because I hear different theories of how propellers generate thrust. One is that the propeller pushes air back to provide thrust. Another is the blades generate lift creating ...
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If engine rotation was in reverse would it result in some kind of thrust reverser? [duplicate]

I mean if you rotated the propeller the other way would it result in reverse thrust.I wonder this because the propeller has to rotate in a certain direction to produce thrust, but would putting it in ...
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How do propeller-driven, fixed-wing UAVs counter negative torque from engine rotation?

What cancels the rolling moment produced from the rotation of the engine?
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Does the direction of counter-rotating props affect efficiency?

From my brief Wikipedying, if counter-rotating props' tops go towards each other, each has a reduced P-factor so the loss of either engine won't yaw the aircraft as hard as if the bottoms come ...
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How do the blades on a propeller generate thrust?

I am having trouble understanding how this type of propeller generates thrust: It is so much different than a propeller on a Cessna and thrust would be provided differently. I am also confused of how ...
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Is it possible to get a list of Cl/Cd values for various NACA Airfoils?

There are a lot of links which give the shape of the airfoil for any given set of camber thickness, position and max. thickness values, but I would like to know if it is possible to get the Lift vs. ...
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Can a plane fly backward if its propeller is in reverse?

I would like to know if a prop plane, for example the P-51, could be able to fly backward. Is it possible through some trick like changing blade angle or reverse the prob rotation direction? It would ...
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Has a general aviation twin-engine turboprop with counter rotating propellors ever been built?

In my experience with general aviation twin-engine turboprops I've never heard of one with counter rotating propellors. I've never seen any data about an engine manufacturer building left-rotating ...
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Why does the Cessna 172S Skyhawk use only two blade fixed pitched prop?

Surely it would get more thrust from a three blade variable pitch propeller. From what I've read it's all about the area swept and also should be far enough apart to not cause too much interference. ...
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Do propeller planes give contrails like jets do?

Last weekend, while watching the second world war film "Fury" with a friend, there was a scene near the end with a large set of bombers flying overhead, leaving large contrails. That seemed wrong to ...
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What is the difference between types of propeller? [closed]

I have been noticing almost every Multirotor vehicle uses a single thin double-bladed propellor on each axis. And yet clearly, there are some that do not fit the norm. Can someone explain what the ...
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Does P-Factor increase with thrust?

I was trying flightgear simulator since I am not a pilot (but have completed ground school) and one thing I have noticed is that the P-Factor increases with thrust applied whether taking off or in ...
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How much energy/prop efficiency does the e-volo copter sacrifice by having a smaller propeller?

It seems like on an electric aircraft, it would be very important to have a high energy efficiency. Wouldn't the e-volo copter be much less efficient due to the small radius of the propellers when ...
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Why an external RAT on this early propeller plane at Charlotte?

At the Charlotte airport, I caught a glimpse of the Bellanca 14-9L with State Airlines livery they have on display. They call the Bellanca the first plane with retractable landing gear but that's not ...
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What is P-Factor in Propeller Aerodynamics? [duplicate]

What is the P-Factor when we're talking about a Propeller Aerodynamics ? Thanks
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Electric Airplane - Hybrid / dual type engines how would that work?

If you have an airplane with electric propellers for take off and landing and you have a turbofan/jet to reach higher speeds for cruise. For example, electric propellers can go to 250mph and turbofan ...
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For an electric airplane are propellers the only option for propulsion?

This is for an electric airplane (so no fuels for combustion): Are propellers the only option? Is there a turbine-jet possible with only air intake, electrically compress, and a turbine and nozzle ...
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What prevents a propeller from detaching completely from the engine body?

How does a propeller remain attached to the engine? I know there is a gearbox and/or some other mechanism that transmit the movement but is there any security mechanism that avoids it from completely ...
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Does the airflow from a propeller over a wing contribute to lift? [duplicate]

How I understand it, the perfect propeller would move air rearward at the exact same velocity as the free stream, i.e. the propeller air will merge with the free stream and have no real influence on ...
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What is the purpose of having contra-rotating props on an aircraft?

Why do planes, like the famous XF-11 and the Tu-95, have contra-rotating props? What is their purpose? Image credit: Mike Freer / Touchdown-Aviation / Wikimedia
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What would happen if the blades of a variable pitch prop did not all have the same pitch?

What would happen if one or more of the blades (but not all) on a variable pitch prop would not tilt at the same angle as the other ones? Could this situation happen or is the technology so advanced ...
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What is the propeller efficiency, $μ_p$, of modern propellers for light sport aircraft?

Roskam's book on preliminary design gives a value of 0.7 for "homebuilt" aircraft and 0.8 for general aviation. What explains this difference in propeller efficiency? The content of Roskam's book is ...
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Why do propeller blades not have winglets?

On the first look this question might sound ridiculous and maybe it is. But as propeller blades act by the same physical laws as wings, and winglets reduce the induced drag by quite a bit, then why ...
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Do ducted fans eliminate induced drag?

It has often been said on this site that induced drag on wings is the inevitable result of producing lift over a finite length. Converting this to the realm of propulsion, I assume that propellers ...
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In turboprops, is there a mechanism to prevent the blades running in opposite direction?

Because, it might lead to reverse flow of air and could stall the plane. Is there some mechanism to prevent this? There was a crash in Ireland a few years ago, when the pilot of a small charter plane ...
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Why don't aeroplanes use propellers with more blades like the intake on a fanjet?

The air intake on a fanjet typically has many small angled blades. A wind pump in an American film might have many broad slatted blades. My desk fan has 3 very large scooping blades and seems quite ...
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What are the advantages of the NASA LEAPTech propeller on wing technology?

NASA has detailed experiments with a new type of parallel array of small electric propellers on the leading edge of the wing technology that they are calling LEAPTech. The press release notes that ...
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What are the factors considered while placing a propeller on a plane? [duplicate]

I have read the post where it describes about the push and pull configurations of the engine, advantages/dis-advantages in them but not the purpose. I have seen images of a figter where the ...
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1answer
3k views

What causes a run-away propeller?

I've never understood this, why can't you just idle the engine and let it slow down?
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Why did the B-29 have so much leftward torque at take-off?

In this book, The Making of the Atomic Bomb by Richard Rhodes (p. 705), I read: [Paul Tibbets] eased the brakes [of Enola Gay] at 0245, the four fuel-injected Wright Cyclone engines pounding. “The ...
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How is the Angle of Attack influenced in the slipstream of a propeller?

My question is how can the angle of attack be changed when the wing is in the slipstream of a propeller, giving "enough air flow" to the wing. The propeller sends the flow of air in the same direction ...